The present invention relates to a photoconductive element unit which is removably mounted in an image-forming apparatus.
Many of modern electronic copiers, electrostatic copiers, facsimile apparatus, and other image-forming apparatus of the type using a belt for a photoconductive element are furnished with a removable photoconductive element unit. Specifically, the photoconductive element unit includes a belt which is passed over a drive roller and driven rollers, and a cleaning device made up of a cleaning means for removing toner which remains on the belt after image transfer and a container for collecting the removed toner. A single housing which accommodates the belt and the cleaning device therein is removably mounted in the image-forming apparatus and may readily be replaced with another by the hand.
A prior art photoconductive element unit of the type described is not designed to allow the cleaning device, which consists of the cleaning means and container as stated above, to be removed from the unit for replacement. Also, the container is hermetically closed so that the toner collected therein cannot be taken out to be disposed of. However, due to the increase in the life of a photoconductive element which owes to the recent progress of technology, it is getting difficult to collect in the container the whole amount of toner which may be removed from the belt before the life of the belt expires. In addition, a cleaning blade, a fur brush and others which serve as a toner collecting means become unusable due to aging before the expiration of the life of the belt.
Therefore, a problem with the prior art photoconductive element unit is that, because the cleaning device cannot be removed and because the toner once collected in the container cannot be taken out, the whole unit inclusive of the belt has to be replaced when the container becomes full or when the cleaning means becomes unusable, even if the belt is still usable. When the belt is scratched or otherwise damaged, too, the unit has to be disposed of with the cleaning device contained therein. Such not only wastes limited resources but also increases the running cost of the aparatus. A container capable of accommodating the whole amount of toner throughout the life of the belt would be too great in dimensions to be accommodated in a limited space available in the apparatus.